A Korean Market in Rivonia Junction in Rivonia Rd, Johannesburg have 19x19 boards. These are folding boards and have a Chinese Chess set on the back. They also have stones which are smaller than standard stones however. These are the best boards i've found in South Africa
Rivonia Square in Rivonia Rd, Johannesburg. There's a little shop with wooden puzzles and things that have 19x19 boards. These boards are very small though, the stones are very small and not easy to play with. I've forgotten the name of the store.